The invention relates generally to safely disposing of biologically-contaminated material, and more particularly to a method for sterilizing biological waste, e.g., medical and/or infectious waste. The invention also relates to disposing of the sterilized biological waste, and to a biomass fuel product made from the waste.
As used herein, "biological waste" has a broad meaning and includes refuse, garbage, waste, etc. that is or is perceived to be capable of transmitting disease rather readily, and biological materials considered to be hazardous to humans or to selected living matter, e.g., refuse, garbage, waste, or other material that contains infectious or other microorganisms. Biological waste thus includes medical and infectious wastes, but would exclude industrial garbage and refuse.
The management, handling and disposal of biological waste has become a matter of increasing concern in recent years both to the public, to health care providers and to medical, research and biological laboratories. Nationally, hospitals are the major generators of medical waste, producing in excess of 500,000 tons each year in the United States. Many states concerned with the growing threat of Acquired Immune Deficiency Syndrome (AIDS) have caused more and more articles and materials to come under the definition of medical waste, which is expected to more than double the amount of medical waste being generated. The health and environmental dangers posed by biological waste mandate that special collection, transportation and disposal techniques be developed.
Hospitals, doctors offices, dentists offices, laboratories, nursing homes, funeral homes and private residences are all legally liable for the safe and effective disposal of medical waste.
The federal Medical Waste Tracking Act of 1988 (Public Law 100-82, Nov. 1, 1988, 102 Stat. 2950) established standards for the tracking and management of all medical waste including the following: cultures and stocks of infectious agents; human blood and blood products; human pathological waste, including those from surgery and autopsy; contaminated animal carcasses from medical research; waste from patients isolated with highly communicable diseases; and all used sharp implements, such as needles and scalpels, as well as certain unused sharp objects in facilities of the type described above.
Sterilization of biological waste is a safe, cheap and practical method of solid waste management and disposal, which avoids the environmental costs of incineration and which limits public exposure to biologically hazardous materials.
Conventional waste sterilization processes are typically batch processes and typically employ either dry heat or steam and a pressurized container. Such processes typically require that the waste remain at least one hour in the pressurized container to complete a batch cycle. Those processes have the disadvantage of high capital and operating costs due to high pressure operation, particularly for the construction and operation of a high pressure vessel large enough to provide a high batch throughput. Other waste sterilization processes employ radiation and/or various chemical agents; these processes have the disadvantage that they generate secondary environmental problems. Still another waste sterilization process employs microwave heating of the biological waste; this process has the disadvantage of high capital and operating costs.